Specific Process Knowledge/Thermal Process/Oxidation
Oxidation
At Danchip we have six furnaces for oxidation: A1,A3,C1,C2,C3 and D1. Oxidation can take place either by a dry process or a wet process. The film quality of dry oxide is better than for wet oxide with regards to density and ? If the film quality for the wet oxide is acceptable then the thickness and the time it takes to grow the oxide often decides if a dry or wet oxidation is chosen.
- Dry oxide is used from 5nm - 200nm. Can be grown in furnaces:A1,A3,C1,C2,C3.
- Wet oxide with O2 and H2 can be grown in furnace:A1,A3.
- Wet oxide with H2O in a bobler can be grown in furnaces:C1,C2,C3.
Comparing the six oxidation furnaces
| ' | A1 Boron drive-in | A3 Phosphorous drive-in | C1 Gate oxide | C2 Anneal oxide | C3 Anneal bond | D1 APOX |
| General description | Drive-in of boron deposited in the boron pre-dep furnace(A2) or drive-in of ion implanted boron. Can also be used for dry and wet oxidation. | Drive-in of phosphorous deposited in the phosphorous pre-dep furnace(A2) or drive-in of ion implanted phosphorous. Can also be used for dry and wet oxidation. | Oxidation of gate-oxide and other especially clean oxides. At the moment also used for general oxidation of 6" wafers. | Oxidation and annealing of wafers from the B-stack and PECVD1. | Oxidation and annealing of wafers from NIL. | Oxidation of very thick oxides |
|---|---|---|---|---|---|---|
| Dry oxidation | x | x | x (with special permission) | x | x | |
| wet oxidation with torch (H2+O2) | x | x | ||||
| Wet oxidation with bubler (water steam + N2) | x (with special permission) | x | x | x | ||
| Process temperature | 800-1150 oC | 800-1150 oC | 800-1150 oC | 800-1150 oC | 800-1150 oC | 1150 oC |
| Cleanliness of dry oxide (rated 1-4, 1 is best) | 2 | 2 | 1 | 3 | 4 | |
| Cleanliness of wet oxide (rated 1-4, 1 is best) | 1 | 1 | 2 | 3 | 4 | 3 |
| Batch size | max. 30 wafers of 4" or 2" | max. 30 4" wafers or 2" wafers | max. 30 wafers of 6",4" or 2" | max. 30 4" wafers or 2" wafers | max. 30 4" wafers or 2" wafers | max. 200 4" |
| Which wafers are allowed to enter the furnace: | A1 Boron drive-in | A3 Phosphorous drive-in | C1 Gate oxide | C2 Anneal oxide | C3 Anneal bond | D1 APOX |
| New clean* Si wafers 4" (6" in C1) | x | x | x (with special permission) | x | x | x |
| RCA clean** Si wafers with no history of Metals on | x | x | x (with special permission) | x | x | |
| From Predep furnace directly (e.g. incl. Predep HF**) | From A2 | From A4 | ||||
| Wafers directly from PECVD1 | x | x | ||||
| Wafers directly from NIL bonding | x |